Abstract - Debaryomyces hansenii, added to the lactic acid bacteria starters in the production of Pecorino Romano cheese, developed even in the interior of the cheese wheels, consuming lactic and acetic acids. This behaviour is important in the nutritional inhibition of Clostridium tyrobutyricum and Cl. butyricum. In the cheeses where yeast growth was greater, ripening was more accelerated, and quality was very good; the final product was typical.This investigation was supported by a grant received from the Consiglio Nazionale delle Ricerche (C.N.R.) Roma